| |
 Unit
# 5 - Calculations
Based on Formulas
Empirical and Molecular Formulae
| Write the empirical
formula for each of the following. |
|
1.(a) |
C8H18, octane
|
|
|
(b) |
C12H22O11, sugar
|
|
|
(c) |
H2S, hydrogen sulfide
|
|
|
(d) |
C2H6O2, ethylene
glycol (antifreeze)
|
|
| 2. From the following empirical formulas
and the formula masses for each compound, determine their molecular formulas. |
|
|
(a) |
CH3; formula mass= 30.0 amu |
|
|
(b) |
CH2; formula mass= 84.0 amu |
|
|
(c) |
C3H4O3 (Vitamin
C); formula mass= 176 amu |
|
| 3. Determine the empirical
formula for a compound that contains 18.6 g of phosphorus and 14.0 g
of nitrogen. |
|
|
| 4. Determine the empirical
formula for a compound that contains 35.6 % of phosphorus and 64.4 %
of sulfur. |
|
|
| 5. A compound with a molecular
mass of 98.0 g/mole was determined to be 24.49 % carbon, 4.08 % hydrogen,
and 72.43 % chlorine. |
| (a) |
Determine the empirical formula of the compound. |
|
| (b) |
Determine the molecular
formula of the compound. |
|
|
